Most mutations have no effect on organisms. Organisms all have large amounts of genetic code, most of which has no effect. As a result, mutation of this code is rarely meaningful.
Air pressure (inside the lungs) is lowest when lung volume is highest, so the answer is B. when you breathe in your lungs expand, which makes the air molecules spread out, therefore the pressure is lower.
The reason for the loss of color after the industrial revolution is that the light-colored moths were "selected against" by predators. These birds could only see the light ones against the newly dark, sooted background. Over time, these predators could no longer distinguish the dark ones from their natural dark, sooted background. Thus more light-colored moths stood out against the dark soot, and were eaten. And more dark-colored moths eluded the birds, survived to reproduce, passing on more of their dominant genes for dark color to their offspring. After several decades of hundreds of thousands of generations, most of the later generations were dark, due to selective advantage of camouflage to survive predation.
Direct observation is an observation you make first hand. It is something you see with your own eyes and observe yourself.
Hope this helps!
